Nothing short of the second coming of Christ will ever make players say WoW isnt dying, and the playerbase has an atrocious memory when it comes to being objective about old expansions compared to new ones.
10.0 will have to be completely awful to not get a pass on quality to begin with once we are straight out of SL. The question is whether it will manage to keep some of that momentum going for long enough that players accept it's good for real.